Hematocrit-Independent Glucose Measurement via Multi-Voltage Electrochemical Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrochemical glucose test strips face inaccuracies in glucose measurement due to high or low hematocrit levels in blood samples, which affect viscosity and oxygen content, leading to incorrect glucose concentration readings.
Innovation Solution
A method involving multiple test voltages applied to a test strip with a reagent layer, where current values are measured and processed using an algorithm to calculate a substantially hematocrit-independent glucose concentration, without the need for a separate blood filtering membrane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single test voltage is applied to measure glucose concentration, then the measurement process is simple and quick, but the measurement accuracy deteriorates due to hematocrit interference
Solution Approach 1:
The measurement process is segmented into multiple discrete voltage application steps (first test voltage, second test voltage, and rest voltage steps) rather than using a single continuous measurement. This segmentation allows the system to collect multiple current values that can be processed to eliminate hematocrit interference, thereby improving measurement precision without significantly increasing operational complexity for the user.
Solution Approach 2:
The patent employs periodic application of different test voltages (alternating between first and second test voltages with rest periods) to the electrodes. This periodic action generates a series of current measurements that capture different aspects of the electrochemical response, enabling the calculation algorithm to distinguish between glucose-related current and hematocrit-related current, thus improving accuracy through time-dependent measurement patterns.
2Measurement precision
If multiple test voltages are applied to eliminate hematocrit interference, then measurement accuracy improves, but the measurement time increases
Solution Approach 1:
The patent applies a series of voltage steps that may seem excessive for a simple glucose measurement, but these additional steps are optimized to complete quickly. The first and second test voltages are applied for limited durations just sufficient to obtain reliable current values, and rest periods are kept brief. This partial/excessive action ensures hematocrit compensation is achieved while minimizing the total time penalty.
Solution Approach 2:
The measurement process maintains continuous useful action by immediately transitioning between voltage steps without idle periods. The first test voltage step is followed directly by the second test voltage step with minimal interruption, and rest periods are used productively for signal stabilization rather than idle time. This continuous progression through multiple measurement phases reduces overall measurement time while still achieving hematocrit-independent results.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves the accuracy of glucose measurement by reducing the impact of hematocrit levels, providing a more reliable and efficient method for determining glucose concentration in various blood samples.
Implementation Method 1
The measurement of glucose is based upon the specific oxidation of glucose by the flavo-enzyme glucose oxidase. During the reaction in Equation 1, the oxidized enzyme GO(ox) is converted to its reduced state which is denoted as GO(red). Next, the reduced enzyme GO(red) is re-oxidized back to GO(ox) by reaction with Fe(CN)63−
Implementation Method 2
GO(red)+2Fe(CN)63−→GO(ox)+2Fe(CN)64−. During the re-generation of GO(red) back to its oxidized state GO(ox), Fe(CN)63− is reduced to Fe(CN)64−. When the reactions set forth above are conducted with a test voltage applied between two electrodes, a test current may be created by the electrochemical re-oxidation of the reduced mediator at the electrode surface.
Implementation Method 3
A mediator, such as ferricyanide, is a compound that accepts electrons from an enzyme such as glucose oxidase and then donates the electrons to an electrode. As the concentration of glucose in the sample increases, the amount of reduced mediator formed also increases, hence, there is a direct relationship between the test current resulting from the re-oxidation of reduced mediator and glucose concentration.
Data Source
AI summary
A method and system is provided to allow for determination of substantially Hematocrit independent analyte concentration. In one example, an analyte measurement system is provided that includes a test strip and a test meter. The test strip includes a reference electrode and a working electrode, in which the working electrode is coated with a reagent layer. The test meter includes an electronic circuit and a signal processor. The electronic circuit applies a plurality of voltages to the reference electrode and the working electrode over respective durations. The signal processor is configured to determine a substantially hematocrit-independent concentration of the analyte from a plurality of current values as measured by the processor upon application of a plurality of test voltages to the reference and working electrodes over a plurality of durations interspersed with rest voltages lower than the test voltages being applied to the electrodes.